Lead-free reflow soldering is the use of the same process as the tin-lead soldering temperature to deal with lead-free. This practice has many advantages due to the low temperature. For example, the equipment needs to be replaced, the power consumption is low, the risk of device damage is small, and so on. However, this process places high demands on DFM as well as reflow soldering. It is necessary for the user to have a good grasp of the adjustment principle of the reflow soldering process, the compensation of negligence, etc. Jinuosi Electronics shares the differences and performance of lead-free reflow soldering.
The difference between lead-free reflow and leaded reflow.
The whole process of SMT lead-free reflow soldering is not much different from leaded resoldering, and it is still the following: steel plate printing solder paste, device placement (high-speed placement of flake-like forced components, and active placement of large-shaped components with special-shaped parts), hot air reflow soldering, cleaning and quality inspection, etc. The difference is that the melting point of lead-free solder paste increases, the solderability deteriorates, the number of empty monuments increases, the board is easy to burst, and the moisture-sensitive seals are more susceptible to damage, etc., and it is necessary to change the concept from the beginning. In fact, according to the experience of mass production for many years, there are only four key reasons that affect the quality of reflow soldering: the solder paste itself, the printing parameters, the quality of the reflow oven and the selection of the reflow soldering curve. Those who have a good grasp of most of the problems can deal with most of the problems.
There are several main advantages of lead-free reflow soldering.
1.High precision: lead-free reflow soldering temperature control accuracy 2.
2.Powerful: there is a circuit board preheater, lead-free soldering, lead-free soldering, chip aging, red glue curing.
3.Inner and outer arc design: Lead-free reflow soldering helps to evenly flow hot air, making the process curve more standard.
4.Process automation: lead-free reflow soldering to achieve fully automatic precision lead-free soldering; The entire process curve is fully controlled, and lead-free reflow soldering can complete the double-sided placement or mixed soldering process.
Lead-free reflow skills.
Lead reflow soldering equipment is generally equipped with a flux management system to avoid the high-temperature gas flow of many fluxes entering the cooling zone and condensing in the heat sink and furnace body, reducing the cooling efficiency and contaminating the equipment.
The lead-free reflow soldering system is to extract the high-temperature gas stream containing many fluxes from the preheating zone, reflow zone and cooling zone, and send the clean gas back to the furnace after the external cooling system. If the production volume is not very large and the flux contamination is small, it can be cleaned up on time without replacement. Vacuum nitrogen furnace.
Lead-free reflow soldering is a type of reflow soldering. In the early years, the solder used for reflow soldering was made of lead-containing materials. With the deepening of people's environmental thinking, more and more attention has been paid to lead-free skills (i.e., today's lead reflow soldering). The changes in materials, especially in solder, are significant. In terms of process, it is the welding process that has a big impact. This is mainly due to the characteristics of the solder alloy and the corresponding flux.